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new 2fdb6870294 KAFKA-19082: [2/4] Add preparedTxnState class to Kafka
Producer (KIP-939) (#19470)
2fdb6870294 is described below
commit 2fdb687029499d33f4a89be08285d565973b403b
Author: Ritika Reddy <[email protected]>
AuthorDate: Tue Apr 29 11:52:02 2025 -0700
KAFKA-19082: [2/4] Add preparedTxnState class to Kafka Producer (KIP-939)
(#19470)
This is part of the client side changes required to enable 2PC for
KIP-939
New KafkaProducer.PreparedTxnState class is going to be defined as
following: ``` static public class PreparedTxnState { public String
toString(); public PreparedTxnState(String serializedState); public
PreparedTxnState(); } ``` The objects of this class can serialize to
/ deserialize from a string value and can be written to / read from a
database. The implementation is going to store producerId and epoch in
the format **producerId:epoch**
Reviewers: Artem Livshits <[email protected]>, Justine Olshan
<[email protected]>
---
.../kafka/clients/producer/PreparedTxnState.java | 128 ++++++++++++++
.../clients/producer/PreparedTxnStateTest.java | 196 +++++++++++++++++++++
2 files changed, 324 insertions(+)
diff --git
a/clients/src/main/java/org/apache/kafka/clients/producer/PreparedTxnState.java
b/clients/src/main/java/org/apache/kafka/clients/producer/PreparedTxnState.java
new file mode 100644
index 00000000000..b5ee45e807d
--- /dev/null
+++
b/clients/src/main/java/org/apache/kafka/clients/producer/PreparedTxnState.java
@@ -0,0 +1,128 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.clients.producer;
+
+import org.apache.kafka.common.record.RecordBatch;
+
+/**
+ * Class containing the state of a transaction after it has been prepared for
a two-phase commit.
+ * This state includes the producer ID and epoch, which are needed to commit
or abort the transaction.
+ */
+public class PreparedTxnState {
+ private final long producerId;
+ private final short epoch;
+
+ /**
+ * Creates a new empty PreparedTxnState
+ */
+ public PreparedTxnState() {
+ this.producerId = RecordBatch.NO_PRODUCER_ID;
+ this.epoch = RecordBatch.NO_PRODUCER_EPOCH;
+ }
+
+ /**
+ * Creates a new PreparedTxnState from a serialized string representation
+ *
+ * @param serializedState The serialized string to
deserialize.
+ * @throws IllegalArgumentException if the serialized string is not in the
expected format
+ */
+ public PreparedTxnState(String serializedState) {
+ if (serializedState == null || serializedState.isEmpty()) {
+ this.producerId = RecordBatch.NO_PRODUCER_ID;
+ this.epoch = RecordBatch.NO_PRODUCER_EPOCH;
+ return;
+ }
+
+ try {
+ String[] parts = serializedState.split(":");
+ if (parts.length != 2) {
+ throw new IllegalArgumentException("Invalid serialized
transaction state format: " + serializedState);
+ }
+
+ this.producerId = Long.parseLong(parts[0]);
+ this.epoch = Short.parseShort(parts[1]);
+
+ // Validate the producerId and epoch values.
+ if (!(this.producerId >= 0 && this.epoch >= 0)) {
+ throw new IllegalArgumentException("Invalid producer ID and
epoch values: " +
+ producerId + ":" + epoch + ". Both must be >= 0");
+ }
+ } catch (NumberFormatException e) {
+ throw new IllegalArgumentException("Invalid serialized transaction
state format: " + serializedState, e);
+ }
+ }
+
+ /**
+ * Creates a new PreparedTxnState with the given producer ID and epoch
+ *
+ * @param producerId The producer ID
+ * @param epoch The producer epoch
+ */
+ PreparedTxnState(long producerId, short epoch) {
+ this.producerId = producerId;
+ this.epoch = epoch;
+ }
+
+ public long producerId() {
+ return producerId;
+ }
+
+ public short epoch() {
+ return epoch;
+ }
+
+ /**
+ * Checks if this preparedTxnState represents an initialized transaction
with a valid producer ID
+ * that is not -1 (the uninitialized value).
+ *
+ * @return true if the state has an initialized transaction, false
otherwise.
+ */
+ public boolean hasTransaction() {
+ return producerId != RecordBatch.NO_PRODUCER_ID;
+ }
+
+ /**
+ * Returns a serialized string representation of this transaction state.
+ * The format is "producerId:epoch" for an initialized state, or an empty
string
+ * for an uninitialized state (where producerId and epoch are both -1).
+ *
+ * @return a serialized string representation
+ */
+ @Override
+ public String toString() {
+ if (!hasTransaction()) {
+ return "";
+ }
+ return producerId + ":" + epoch;
+ }
+
+ @Override
+ public boolean equals(Object o) {
+ if (this == o) return true;
+ if (o == null || getClass() != o.getClass()) return false;
+ PreparedTxnState that = (PreparedTxnState) o;
+ return producerId == that.producerId && epoch == that.epoch;
+ }
+
+ @Override
+ public int hashCode() {
+ int result = 31;
+ result = 31 * result + Long.hashCode(producerId);
+ result = 31 * result + (int) epoch;
+ return result;
+ }
+}
diff --git
a/clients/src/test/java/org/apache/kafka/clients/producer/PreparedTxnStateTest.java
b/clients/src/test/java/org/apache/kafka/clients/producer/PreparedTxnStateTest.java
new file mode 100644
index 00000000000..f0d94434d47
--- /dev/null
+++
b/clients/src/test/java/org/apache/kafka/clients/producer/PreparedTxnStateTest.java
@@ -0,0 +1,196 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.kafka.clients.producer;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * Tests for the PreparedTxnState class part of the #KafkaProducer class.
+ */
+public class PreparedTxnStateTest {
+
+ @Test
+ public void testDefaultConstructor() {
+ PreparedTxnState state = new PreparedTxnState();
+ assertEquals("", state.toString(), "Empty state should serialize to an
empty string");
+ assertEquals(-1L, state.producerId(), "Default producerId should be
-1");
+ assertEquals((short) -1, state.epoch(), "Default epoch should be -1");
+ assertFalse(state.hasTransaction(), "Default state should not have a
transaction");
+ }
+
+ @Test
+ public void testParameterizedConstructor() {
+ long producerId = 123L;
+ short epoch = 45;
+ PreparedTxnState state = new PreparedTxnState(producerId, epoch);
+ assertEquals(producerId, state.producerId(), "ProducerId should
match");
+ assertEquals(epoch, state.epoch(), "Epoch should match");
+ assertTrue(state.hasTransaction(), "State should have a transaction");
+ assertEquals("123:45", state.toString(), "Serialized form should match
expected format");
+ }
+
+ @Test
+ public void testDeserializationFromString() {
+ String serialized = "123:45";
+ PreparedTxnState state = new PreparedTxnState(serialized);
+ assertEquals(serialized, state.toString(), "Deserialized state should
match the original serialized string");
+ assertEquals(123L, state.producerId(), "Deserialized producerId should
match");
+ assertEquals((short) 45, state.epoch(), "Deserialized epoch should
match");
+ assertTrue(state.hasTransaction(), "Deserialized state should have a
transaction");
+ }
+
+ @Test
+ public void testRoundTripSerialization() {
+ // Create initialized state from string, then convert back to string
+ String original = "9876:54";
+ PreparedTxnState state = new PreparedTxnState(original);
+ String serialized = state.toString();
+ assertEquals(original, serialized, "Round-trip serialization should
preserve values");
+
+ // Deserialize again to verify
+ PreparedTxnState stateAgain = new PreparedTxnState(serialized);
+ assertEquals(original, stateAgain.toString(), "Re-deserialized state
should match original");
+ assertEquals(state.producerId(), stateAgain.producerId(), "Producer
IDs should match");
+ assertEquals(state.epoch(), stateAgain.epoch(), "Epochs should match");
+
+ // Test round trip for uninitialized state (empty string)
+ String emptyString = "";
+ PreparedTxnState emptyState = new PreparedTxnState(emptyString);
+ String emptyStateSerialized = emptyState.toString();
+ assertEquals(emptyString, emptyStateSerialized, "Round-trip of empty
string should remain empty");
+ assertEquals(-1L, emptyState.producerId(), "Empty string should result
in producerId -1");
+ assertEquals((short) -1, emptyState.epoch(), "Empty string should
result in epoch -1");
+
+ // Deserialize empty state again to verify
+ PreparedTxnState emptyStateAgain = new
PreparedTxnState(emptyStateSerialized);
+ assertEquals(emptyString, emptyStateAgain.toString(), "Re-deserialized
empty state should still be empty");
+ assertEquals(-1L, emptyStateAgain.producerId(), "Empty string should
result in producerId -1");
+ assertEquals((short) -1, emptyStateAgain.epoch(), "Empty string should
result in epoch -1");
+ }
+
+ @Test
+ public void testHandlingOfNullOrEmptyString() {
+ PreparedTxnState stateWithNull = new PreparedTxnState(null);
+ assertEquals("", stateWithNull.toString(), "Null string should result
in empty state");
+ assertFalse(stateWithNull.hasTransaction(), "State from null string
should not have a transaction");
+
+ PreparedTxnState stateWithEmpty = new PreparedTxnState("");
+ assertEquals("", stateWithEmpty.toString(), "Empty string should
result in empty state");
+ assertFalse(stateWithEmpty.hasTransaction(), "State from empty string
should not have a transaction");
+ }
+
+ @Test
+ public void testMaxValues() {
+ // Test with maximum possible values for producer ID and epoch
+ String maxValues = Long.MAX_VALUE + ":" + Short.MAX_VALUE;
+ PreparedTxnState state = new PreparedTxnState(maxValues);
+ assertEquals(maxValues, state.toString(), "Max values should be
handled correctly");
+ assertEquals(Long.MAX_VALUE, state.producerId(), "Max producer ID
should be handled correctly");
+ assertEquals(Short.MAX_VALUE, state.epoch(), "Max epoch should be
handled correctly");
+ assertTrue(state.hasTransaction(), "State with max values should have
a transaction");
+ }
+
+ @Test
+ public void testEqualsAndHashCode() {
+ PreparedTxnState state1 = new PreparedTxnState(123L, (short) 45);
+ PreparedTxnState state2 = new PreparedTxnState(123L, (short) 45);
+ PreparedTxnState state3 = new PreparedTxnState(456L, (short) 78);
+ PreparedTxnState state4 = new PreparedTxnState(123L, (short) 46);
+
+ // Test equals
+ assertEquals(state1, state2, "Equal states should be equal");
+ assertNotEquals(state1, state3, "States with different producer IDs
should not be equal");
+ assertNotEquals(state1, state4, "States with different epochs should
not be equal");
+ assertNotEquals(null, state1, "State should not equal null");
+
+ // Test hashCode
+ assertEquals(state1.hashCode(), state2.hashCode(), "Equal states
should have same hash code");
+ assertNotEquals(state1.hashCode(), state3.hashCode(), "Different
states should have different hash codes");
+ }
+
+ @Test
+ public void testHasTransaction() {
+ // State with transaction (producer ID >= 0)
+ PreparedTxnState stateWithTransaction = new PreparedTxnState(0L,
(short) 0);
+ assertTrue(stateWithTransaction.hasTransaction(), "State with
producerId 0 should have a transaction");
+
+ // State without transaction (producer ID = -1)
+ PreparedTxnState stateWithoutTransaction = new PreparedTxnState(-1L,
(short) -1);
+ assertFalse(stateWithoutTransaction.hasTransaction(), "State with
producerId -1 should not have a transaction");
+ }
+
+ @Test
+ public void testInvalidFormatThrowsException() {
+ // Test with invalid format - missing epoch
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("123"),
+ "String with missing epoch should throw IllegalArgumentException");
+
+ // Test with invalid format - too many parts
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("123:45:67"),
+ "String with extra parts should throw IllegalArgumentException");
+
+ // Test with non-numeric producer ID
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("abc:45"),
+ "Non-numeric producer ID should throw IllegalArgumentException");
+
+ // Test with non-numeric epoch
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("123:xyz"),
+ "Non-numeric epoch should throw IllegalArgumentException");
+ }
+
+ @Test
+ public void testInvalidProducerIdEpochCombinations() {
+ // Valid combinations: both >= 0
+ new PreparedTxnState("0:0");
+ new PreparedTxnState("123:45");
+
+ // Invalid: producerId >= 0, epoch < 0
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("123:-2"),
+ "Positive producerId with negative epoch (not -1) should throw
IllegalArgumentException");
+
+ // Invalid: producerId < 0 (not -1), epoch >= 0
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("-2:45"),
+ "Negative producerId (not -1) with positive epoch should throw
IllegalArgumentException");
+
+ // Invalid: producerId < 0 (not -1), epoch < 0 (not -1)
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("-2:-2"),
+ "Negative producerId and epoch (not -1) should throw
IllegalArgumentException");
+
+ // Invalid: producerId = -1, epoch >= 0
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("-1:45"),
+ "ProducerId -1 with positive epoch should throw
IllegalArgumentException");
+
+ // Invalid: producerId >= 0, epoch = -1
+ assertThrows(IllegalArgumentException.class,
+ () -> new PreparedTxnState("123:-1"),
+ "Positive producerId with epoch -1 should throw
IllegalArgumentException");
+ }
+}
